A conventional strings or central inverter device comprises multiple solar panels that are connected to a centralized inverter system. Solar panels are wired in series, creating a PV array, that is then connected to a string or a central inverter that converts the direct current (DC) from the PV array into an alternating current (AC). However, the performance of these conventional central inverter devices suffer from a number of disadvantages such as sub-optimal energy harvest, safety concern for DC wiring, short life, complex array design and installation, and difficulty in determining the location of performance problems.
On the contrary, a solar micro-inverter is a system that converts direct current (DC) from a single solar panel to an alternating current (AC). The electric power from several micro-inverters is combined and fed into an existing electrical grid. A solar micro-inverter offers various advantages over the conventional strings or central inverter systems. The main advantage is that even small amount of shading, debris or snow line in any one solar panel, or a panel failure do not disproportionately reduce the output of the entire array. Each micro-inverter obtains optimum power by performing maximum power point tracking for its connected panel.
The micro-inverters are located near the panel. The micro-inverters are equipped with a communication unit that enables monitoring the performance of each panel and controlling the micro-inverter for maintenance and troubleshooting purposes. The communication is typically performed using a powerline communication or a near range wireless modem. The micro-inverter controller is coupled to the powerline communication or a wireless modem using a suitable interface. The problem associated with this micro-inverter modem arrangement is that it includes redundant processing units optimized for very specific functions such as analog controller, modem and even an additional processor for Arc detection as a safety precaution, ultimately resulting in increased cost.
In light of the foregoing discussion, an improved micro-inverter arrangement is desirable whereby a single processor can implement the modem function as well as the micro-inverter control and any other computational function, and hence eliminates the need for a standalone modem and a separate controller or any other separate control or monitoring processors.